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Using brain-computer interfaces and brain-state dependent stimulation as tools in cognitive neuroscience.

Jensen O, Bahramisharif A, Oostenveld R, Klanke S, Hadjipapas A, Okazaki YO, van Gerven MA - Front Psychol (2011)

Bottom Line: This principle of brain-state dependent stimulation may also be used as a practical tool for augmenting human behavior.In conclusion, new approaches based on online analysis of ongoing brain activity are currently in rapid development.These approaches are amongst others informed by new insight gained from electroencephalography/magnetoencephalography studies in cognitive neuroscience and hold the promise of providing new ways for investigating the brain at work.

View Article: PubMed Central - PubMed

Affiliation: Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen Netherlands.

ABSTRACT
Large efforts are currently being made to develop and improve online analysis of brain activity which can be used, e.g., for brain-computer interfacing (BCI). A BCI allows a subject to control a device by willfully changing his/her own brain activity. BCI therefore holds the promise as a tool for aiding the disabled and for augmenting human performance. While technical developments obviously are important, we will here argue that new insight gained from cognitive neuroscience can be used to identify signatures of neural activation which reliably can be modulated by the subject at will. This review will focus mainly on oscillatory activity in the alpha band which is strongly modulated by changes in covert attention. Besides developing BCIs for their traditional purpose, they might also be used as a research tool for cognitive neuroscience. There is currently a strong interest in how brain-state fluctuations impact cognition. These state fluctuations are partly reflected by ongoing oscillatory activity. The functional role of the brain state can be investigated by introducing stimuli in real-time to subjects depending on the actual state of the brain. This principle of brain-state dependent stimulation may also be used as a practical tool for augmenting human behavior. In conclusion, new approaches based on online analysis of ongoing brain activity are currently in rapid development. These approaches are amongst others informed by new insight gained from electroencephalography/magnetoencephalography studies in cognitive neuroscience and hold the promise of providing new ways for investigating the brain at work.

No MeSH data available.


Related in: MedlinePlus

The topography of the alpha activity is modulated by covert attention in different directions. This opens the possibility of making a BCI system which tracks attention in two dimensions. (A) Subjects were asked to covertly attend to one of eight directions for a 1300-ms period while fixating centrally. During this interval the alpha power was estimated using data from a 128 channel EEG system. The resulting topographies for the eight direction are shown. Both vertical and horizontal directions of covert attention clearly modulated the distribution in the alpha band. Reproduced with permission from Rihs et al. (2007). (B) In an MEG experiment subjects were asked to continuously track the direction of a target moving on a circle while fixating at the central cross. (C) The directions of attention were arbitrarily divided into 16 subparts and the respective alpha power was estimated using at 275 sensor MEG system. The topography of the alpha band activity is clearly modulated by the direction of attention. (D) The direction of covert attention was estimated from 1700 ms data segments. The true angle of the target could be predicted from the alpha activity alone with some error (top panel). After a smoothness constraint was applied (lower panel), the prediction error was much reduced. [(B,C,D), top panel] Reproduced with permission from Bahramisharif et al. (2010b).
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Figure 4: The topography of the alpha activity is modulated by covert attention in different directions. This opens the possibility of making a BCI system which tracks attention in two dimensions. (A) Subjects were asked to covertly attend to one of eight directions for a 1300-ms period while fixating centrally. During this interval the alpha power was estimated using data from a 128 channel EEG system. The resulting topographies for the eight direction are shown. Both vertical and horizontal directions of covert attention clearly modulated the distribution in the alpha band. Reproduced with permission from Rihs et al. (2007). (B) In an MEG experiment subjects were asked to continuously track the direction of a target moving on a circle while fixating at the central cross. (C) The directions of attention were arbitrarily divided into 16 subparts and the respective alpha power was estimated using at 275 sensor MEG system. The topography of the alpha band activity is clearly modulated by the direction of attention. (D) The direction of covert attention was estimated from 1700 ms data segments. The true angle of the target could be predicted from the alpha activity alone with some error (top panel). After a smoothness constraint was applied (lower panel), the prediction error was much reduced. [(B,C,D), top panel] Reproduced with permission from Bahramisharif et al. (2010b).

Mentions: Not only do changes in covert attention in the horizontal plane modulate posterior alpha activity, so do vertical changes. In an EEG study subjects were asked to covertly direct their attention to eight different directions. When inspecting the topographical maps of the alpha activity, there were strong modulations according to the direction of attention (Rihs et al., 2007). When subjects were attending down, the posterior alpha activity was suppressed more so than when attention was directed up. This implies that the vertical direction of covert attention might be used for BCI control as well. In an MEG study in which subject were asked to covertly attend to a symbol in one of four directions (up, down, left, right) it was indeed possible to decode the attended direction in single trials (Van Gerven et al., 2009). This raises the possibility that an arbitrary direction of covert attention can be decoded by taking the topographic distribution of covert attention into account. This was tested in a setup in which subjects were asked to fixate centrally but covertly track the direction of a moving target. Using a sliding time window of 1700 ms it was possible to decode the direction of attention well above chance with a mean absolute deviation between the actual and predicted directions of about 60 degrees for the best case (Bahramisharif et al., 2010b). This error can be considerably reduced if smooth target movement over time is used as an additional constraint. This constraint can be mathematically expressed using a linear dynamical system where the predicted direction of attention not only depends on the alpha activity but also on the previous predicted direction. By virtue of this approach the mean absolute deviation decreased from 60 to 48 degrees for the best case. See Figure 4 for a visualization of these results.


Using brain-computer interfaces and brain-state dependent stimulation as tools in cognitive neuroscience.

Jensen O, Bahramisharif A, Oostenveld R, Klanke S, Hadjipapas A, Okazaki YO, van Gerven MA - Front Psychol (2011)

The topography of the alpha activity is modulated by covert attention in different directions. This opens the possibility of making a BCI system which tracks attention in two dimensions. (A) Subjects were asked to covertly attend to one of eight directions for a 1300-ms period while fixating centrally. During this interval the alpha power was estimated using data from a 128 channel EEG system. The resulting topographies for the eight direction are shown. Both vertical and horizontal directions of covert attention clearly modulated the distribution in the alpha band. Reproduced with permission from Rihs et al. (2007). (B) In an MEG experiment subjects were asked to continuously track the direction of a target moving on a circle while fixating at the central cross. (C) The directions of attention were arbitrarily divided into 16 subparts and the respective alpha power was estimated using at 275 sensor MEG system. The topography of the alpha band activity is clearly modulated by the direction of attention. (D) The direction of covert attention was estimated from 1700 ms data segments. The true angle of the target could be predicted from the alpha activity alone with some error (top panel). After a smoothness constraint was applied (lower panel), the prediction error was much reduced. [(B,C,D), top panel] Reproduced with permission from Bahramisharif et al. (2010b).
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC3108578&req=5

Figure 4: The topography of the alpha activity is modulated by covert attention in different directions. This opens the possibility of making a BCI system which tracks attention in two dimensions. (A) Subjects were asked to covertly attend to one of eight directions for a 1300-ms period while fixating centrally. During this interval the alpha power was estimated using data from a 128 channel EEG system. The resulting topographies for the eight direction are shown. Both vertical and horizontal directions of covert attention clearly modulated the distribution in the alpha band. Reproduced with permission from Rihs et al. (2007). (B) In an MEG experiment subjects were asked to continuously track the direction of a target moving on a circle while fixating at the central cross. (C) The directions of attention were arbitrarily divided into 16 subparts and the respective alpha power was estimated using at 275 sensor MEG system. The topography of the alpha band activity is clearly modulated by the direction of attention. (D) The direction of covert attention was estimated from 1700 ms data segments. The true angle of the target could be predicted from the alpha activity alone with some error (top panel). After a smoothness constraint was applied (lower panel), the prediction error was much reduced. [(B,C,D), top panel] Reproduced with permission from Bahramisharif et al. (2010b).
Mentions: Not only do changes in covert attention in the horizontal plane modulate posterior alpha activity, so do vertical changes. In an EEG study subjects were asked to covertly direct their attention to eight different directions. When inspecting the topographical maps of the alpha activity, there were strong modulations according to the direction of attention (Rihs et al., 2007). When subjects were attending down, the posterior alpha activity was suppressed more so than when attention was directed up. This implies that the vertical direction of covert attention might be used for BCI control as well. In an MEG study in which subject were asked to covertly attend to a symbol in one of four directions (up, down, left, right) it was indeed possible to decode the attended direction in single trials (Van Gerven et al., 2009). This raises the possibility that an arbitrary direction of covert attention can be decoded by taking the topographic distribution of covert attention into account. This was tested in a setup in which subjects were asked to fixate centrally but covertly track the direction of a moving target. Using a sliding time window of 1700 ms it was possible to decode the direction of attention well above chance with a mean absolute deviation between the actual and predicted directions of about 60 degrees for the best case (Bahramisharif et al., 2010b). This error can be considerably reduced if smooth target movement over time is used as an additional constraint. This constraint can be mathematically expressed using a linear dynamical system where the predicted direction of attention not only depends on the alpha activity but also on the previous predicted direction. By virtue of this approach the mean absolute deviation decreased from 60 to 48 degrees for the best case. See Figure 4 for a visualization of these results.

Bottom Line: This principle of brain-state dependent stimulation may also be used as a practical tool for augmenting human behavior.In conclusion, new approaches based on online analysis of ongoing brain activity are currently in rapid development.These approaches are amongst others informed by new insight gained from electroencephalography/magnetoencephalography studies in cognitive neuroscience and hold the promise of providing new ways for investigating the brain at work.

View Article: PubMed Central - PubMed

Affiliation: Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen Netherlands.

ABSTRACT
Large efforts are currently being made to develop and improve online analysis of brain activity which can be used, e.g., for brain-computer interfacing (BCI). A BCI allows a subject to control a device by willfully changing his/her own brain activity. BCI therefore holds the promise as a tool for aiding the disabled and for augmenting human performance. While technical developments obviously are important, we will here argue that new insight gained from cognitive neuroscience can be used to identify signatures of neural activation which reliably can be modulated by the subject at will. This review will focus mainly on oscillatory activity in the alpha band which is strongly modulated by changes in covert attention. Besides developing BCIs for their traditional purpose, they might also be used as a research tool for cognitive neuroscience. There is currently a strong interest in how brain-state fluctuations impact cognition. These state fluctuations are partly reflected by ongoing oscillatory activity. The functional role of the brain state can be investigated by introducing stimuli in real-time to subjects depending on the actual state of the brain. This principle of brain-state dependent stimulation may also be used as a practical tool for augmenting human behavior. In conclusion, new approaches based on online analysis of ongoing brain activity are currently in rapid development. These approaches are amongst others informed by new insight gained from electroencephalography/magnetoencephalography studies in cognitive neuroscience and hold the promise of providing new ways for investigating the brain at work.

No MeSH data available.


Related in: MedlinePlus